Today’s factismal: Thirteen years ago, the Galileo probe made the closest approach ever to Jupiter’s moon Io; it was just 112 miles away from the surface of the moon!
The four largest moons of Jupiter (Io, Europa, Ganymede, and Callisto) have a special place in the minds of all planetologists. They were the first new planets to be discovered in modern times (they were originally called planets; the astronomers only started calling them moons when there were too many to count on the astronomers’ fingers). They helped establish the validity of the Copernican model of the universe and destroy the Earth-centered one. And they helped to establish Galileo’s reputation as a scientist, which then helped change science from a descriptive endeavor to an experimental one.
Though the four Galilean moons are easily visible with a pair of binoculars, it wasn’t until Voyager 1 and 2 passed by that we got our first good look at them. And perhaps the most surprising of the four was Io. A small, rocky world, it was rapidly revealed to be the most volcanically active body in the Solar System. Covered by lava flows and sulfur frost, it was unlike any of the other moons we’ve seen. Obviously, it needed to be explored in more detail.
A close-up image of Io, taken by the Galileo probe
(Image courtesy NASA)
And so we sent out another probe. Launched in 1989 and named Galileo for the discoverer of the four moons, its primary mission was to map Jupiter’s moons and to discover the secrets of Jupiter’s atmosphere using a secondary probe. And, from the time it arrived at Jupiter in 1995 until its final plunge into Jupiter’s atmosphere in 2003, it returned over 14,000 images of Jupiter and its moons that have forever changed the way that we see planetary formation.
If you’d like to learn more about the Galileo probe (or any other planetary probe), then why not join the Association of Lunar and Planetary Observers? They’ve got lots of information on every planet (even Earth), along with several citizen science projects that you can get involved with! http://alpo-astronomy.org/
Today’s factismal: Acid rain has about the same pH level as wine or beer.
In the late 1800s, the fogs of London were notorious not just for their thickness (“pea soup” being about the kindest appellation that they were given) but also for their effect. Going out in a London fog would leave you with a raspy voice, itchy eyes, and a dry, chapped skin. How could a little fog do so much damage? It was because at that time, London was powered almost exclusively by high-sulfur coal. When the sulfur from the coal combined with the water in the fog, it created a weak sulfuric acid solution (about as acidic as wine or beer); walking in the fog was literally like walking in acid!
How acid rain forms
(Image courtesy EPA)
The fogs of London are now nothing but a memory, thanks to improved power generation methods, but acid rain is still with us. There are many places around the world (e.g., China, India) where it is cheaper and easier to burn high sulfur coal and oil to generate energy, which means that there is still plenty of sulfuric acid being formed. And, because the atmosphere doesn’t stop at a country’s borders, the pollution that one nation creates can easily affect other nations across the globe. However, quantifying that damage can be frustratingly difficult.
This fountain has been damaged by acid rain
And that’s where you come in. A group of scientists in Sydney (Utah) are looking for volunteers across the globe to go out and look at old gravestones in order to measure the effects of acid rain. The sulfuric acid created by sulfur pollution will slowly eat away at a marble gravestone; by measuring the amount of damage that’s been done, they can tell how much sulfur pollution the area has had. If you’d like to help, then head over to:
Today’s factismal: This is the start of Earth Science Week – have you hugged a geologist today?
This week is Earth Science Week, celebrating all of the fun that can be found in studying the Earth. (Teachers: The AGI has a special free packet of goodies just for you!) So the posts this week will all be about earth sciences. And to start with, we’ll explore deep time.
The Earth is 4.6 billion years old (give or take a couple of weeks). But most people, heck most geologists, don’t have a good feel for just how long that really is. So I’ve taken the history of the Earth and put it into a time scale that we can appreciate: that of a 45-year old person. Looked at that way, the following events would have marked your life:
- 45 years ago, you were born, just six months after your (much) bigger brother (the Sun). Your brother threw a lot of temper tantrums during the first few months, but seems to be getting more stable.
- 41 days later, you underwent surgery to remove your twin (the Moon).
- When you turned 3, you were allowed to take a bath (oceans formed)
- When you were 4 ¾, you were given your first furniture (rocks) to keep. Every couple of years or so, you re-arrange the furniture and re-upholster a lot of it as you go.
- When you were 6 ½ you got a fungal infection (life appeared on your surface).
- When you were 13 ½, you made a water garden (photosynthesis started). You and your twin are at your closest, but you can feel her growing more distant by the day. About twice a month you catch a chill and then get too hot.
- Not much happened for the next twenty years or so. But when you turned 35, you got crabs! (Arthropods appeared)
- Six months later, you were given a goldfish as a present (fish appeared). Two months after that, you got your first house plant (land plants appeared).
- When you were 36 ½, your plants got aphids (insects appeared).
- During the first part of your 37th year, you bought a lizard (reptiles appeared). During the last half of the year, you noticed that the lizard was getting rather large (dinosaurs appeared).
- Doing your spring cleaning two years ago (your 38th year), you found mouse droppings (mammals appeared). Later that summer, you noticed birds for the first time.
- Just over a year ago, your houseplant sprang into bloom (flowers appeared).
- About six months ago, your pet lizard died, but you can’t figure out why. Was it that accident you had? Or the cold you caught? Or was it changing his Lizard Chow? Or did it happen just because you re-arranged the furniture?
- Just over a week ago, a noisy family moved into the neighborhood (humans appeared). They finally quieted down an hour ago (civilization spread), but you aren’t sure whether or not you want them in your neighborhood especially as they seem intent on throwing crap into your backyard.
There – doesn’t that make you feel better about your mid-life crisis?
For more information on Earth Science Week, head over to the AGI website:
Today’s factismal: Some dinoflagellates use bioluminescence to attract big fish that eat the little fish that eat dinoflagellates.
Obi-wan said it best: “There’s always a bigger fish”. And he probably learned that from dinoflagellates. These tiny little critters have a whip at one end that they use for propulsion, a shell made out of cellulose, and a variety of lifestyles that ranges the gamut from photosynthesis to hunter. Then again, with more than 2,200 species of dinoflagellate, there is plenty of room for just about any oddity. But perhaps the oddest thing that any dinoflagellate species does is flash blue lights when startled or jostled.
Interestingly, it was that blue flash that first attracted people to them; the very first paper written about dinoflagellates was called “Animalcules which cause the Sparkling Light in Sea Water” and it hit the popular press way back in 1753. Today, quite a bit is known about how and why they flash. The reaction is similar to that of the firefly (and uses some of the same chemicals) but it happens for much different reasons. Like the firefly, they flash only at night. However, the firefly flashes in order to attract his lady-love and the dinoflagellate flashes to attract big fish (partly because dinoflagellates don’t have lady-loves. Poor dinoflagellate.). The rapid motion of small fish causes a pressure wave which triggers the flash; this is why they often flash in the wake of boats at sea. And the light that they generate attracts big fish that come to dine on the little fish that are feasting on the dinoflagellate.
A bioluminescent dinoflagellate
(Image courtesy Maria Faust)
And the most interesting thing about the dinoflagellate flash is that it only happens within a specific pH range; if the water is too basic or too acidic, the poor dinoflagellate can’t flash. As a result, some ecologists in San Diego Bay are using the flash as a way of checking the water quality: flashing dinoflagellates means that everybody’s happy (except the big fish that thought it was a call to dinner). If you’d like to join the ecologists as they research more about dinoflagellates and the health of the bay, then head over to:
Today’s factismal: The largest insect known to have ever lived was the Meganeuropsis americana which had a 28 inch wingspan and weighed more than a pound.
Imagine that you are in Oklahoma a mere 265 million years ago. Instead of the rolling prairies that cover Oklahoma today, you are surrounded by a swamp that is filled with amphibians and reptiles. And instead of today’s rather oxygen-deprived atmosphere (a mere 21%), you are in air with 30% oxygen content. That higher oxygen content makes wildfires more common; it also allows many creatures to get much larger than they could today.
And no group of critters does better than the insects; high oxygen levels allow them to grow much larger than is possible today. Of course, there are some paleontologists who believe that the oxygen levels are at best a secondary cause for the bigger insects back then; they argue that there were fewer large predators of insects which allowed for bigger insects to survive. In either case, one thing is sure: insects back then were big. Mosquitoes the size of your hand. Roaches the size of your foot. And primitive dragonflies the size of your desk.
First found in Oklahoma by a Harvard paleontologist in 1947, their fossils are impressive. The best known is a single forewing which stretches 14 inches in length. The limestone that it was found in was known to come from a lake-type environment, which tells us that dragonflies haven’t changed much in their habits in 265 million years. And other evidence tells us that they fed on small reptiles, frogs, newts, and anything else foolish enough to get in their way, just as today’s dragonflies feed on small fish, tadpoles, and other insects.
Though you are unlikely to run into a Meganeuropsis americana today (unless you happen to be in a bad B-movie), you may still see one of its distant great-great-great-grandkids flitting by. If you are that lucky, then why not report it to your local entymologist? Many states have set up portals like the Arizona Odonta site, hoping to get more information on these fascinating fliers.
Today’s factismal: There are 3,600,000 miles of river in the USA.
If you look at the United States from space, one of the first things you’ll notice (apart from the purple mountains’ majesty and fruited plains) is the number of rivers that sprawl across its face. All told, there are more than 250,000 rivers in the USA and they stretch a total of 3,600,000 miles; that’s long enough to circle the Earth 144 times or to reach from here to the Moon fifteen times! (“Moon river…”) Ranging in length from the mighty Missouri (2,540 miles) to the tiny Roe River (201 ft), these riparian passages push 48,000,000 gallons of water and sediment into the ocean every second. If you were to catch the water with Olympic swimming pools, you’d fill up 72 of them every second!
There are 3,600,000 miles of river in the USA
(Image courtesy National Atlas)
Those 250,000 rivers supply water for farming and industry (and drinking). They also serve as efficient transportation for bulk goods like coal, grain, and iron ore; a single 15-barge tow can carry as much cargo as 870 tractor trailer trucks or 225 railroad cars. Yet, even though these rivers are essential to supporting both our life and our economy, nearly half of them are too polluted to fish from!
And that’s why the good citizens of Sherman’s Creek have banded together to monitor their river. These citizen scientists track the amount of oxygen, nitrates, and pollutants in Sherman’s Creek and use the data to help keep their river in swimming hole condition. If you’d like to join them (or just see what a great citizen science project looks like), float on over to:
Today’s factismal: Washington DC has lost nearly one third of its trees since 1950.
What with all of the news coverage of the various disfunctions, malfunctions, and malefactions in our nation’s capitol, you might think that there wasn’t any room for more. Unfortunately, you’d be wrong. There is another problem in Washington, DC, and it is one that you can do something about! But to understand it, we have to set our “wayback machine” to 1790 when George Washington and his fellow Founding Fathers decided to place the capitol on land donated by Virginia and Maryland.
As part of the planning for the city, Washington decided that there should be impressive buildings and even more impressive tree-lined boulevards and tree-filled parks. Falsehoods about cherry trees aside, Washington was an ardent arborist who enjoyed trying to get new and different types of trees to grow. (Franklin beats him on that score, though – Franklin actually has a species of tree named after him!) And so he worked with L’Enfant (the architect of the city) to ensure that there were plenty of places to put trees. Their plan worked so well that DC was known as “the city of trees” during the 1800s.
The Washington Monument, peeking out from the cherry trees
But as Washington became more a place to live and less a place to just work, the trees started getting crowded out by new buildings and new roads. Throughout the last century places that had harbored arbors turned into apartment complexes and shopping malls. As a result, the amount of DC covered by a tree canopy declined from 50% in 1950 to less than 35% in 2011; one-third of the trees and all of the animals and other plants that they harbored had gone!
That inspired one citizen scientist to start a project to replant DC and restore it to its former green glory. She began the eponymous Casey Trees, a citizen science project that helps locals and visitors alike take part in the effort. To learn more, head over to their website: